1. Field of the Invention
The present invention relates to an epoxidized acetylene-conjugated diene random copolymer, of which epoxy equivalent is within the range of from 50 to 1,000, and the curable composition comprising the same.
2. Description of the Prior Art
There have hitherto been known epoxidized products of conjugated diene polymers, such as polybutadiene and the like.
The conventional epoxidized polybutadiene is produced, for example, by reacting polybutadiene with oxygen under oxidation conditions or organic peracid. Though the resulting epoxidized polybutadiene is curable with a proper curing agent for epoxy group, the curing rate and efficiency are not satisfactorily high for various uses, for example, as vehicles, drying oils and base materials of coating or laminate compositions.
It has been well known that acetylene and conjugated diene compounds are considerably different in the polymerization reactivity and therefore the copolymerization of these compounds is very difficult. In general, when the copolymerization reacton is effected in a combination of the monomers having considerably different polymerization reactivities, a mixture of homopolymers of both the monomers or a block copolymer is obtained. For example, Italian Pat. No. 665,277 discloses a method for copolymerizing acetylene and butadiene into a block copolymer.
The random copolymers of acetylene and a conjugated diene compound to be used in the present invention are quite novel copolymers in which acetylene and a conjugated diene compound are bonded linearly and randomly. These copolymers are novel compounds in which the conjugated diene compound units have 1,4-bonds. The 1,4-bonds have cis-type and trans-type but when the conjugated diene is, for example, butadiene or isoprene, these compounds are bonded substantially in cis-type, while in the case of 2,3-dimethylbutadiene, the compound is bonded substantially in trans-type and either cis-type or trans-type is formed. The copolymers in which acetylene and the conjugated diene compound are bonded in a linear random and the conjugated dienes are bonded in either cis-1,5-bond or trans-1,4-bond have never been known and the method for producing said copolymers also has never been known. The inventors have found that the epoxidized acetylene-conjugated diene random copolymer prepared by the present invention shows the more fast curing rate than that of the epoxidized polydiene, and yields the excellent films, coating surfaces and shaped articles.